"Amazing" is not a word usually associated with the giving habits of those who don't believe in God. Rather, studies show they typically score in Scrooge territory. In 2003, social scientist Arthur C. Brooks found religious persons 25 percent more likely to donate money than secularists, and 23 percent more likely to volunteer.

Last year, sociologists and co-authors Robert Putnam and David Campbell found a six-in-10 chance that a person who never attends church will give money to a secular charity, while the figure for religious people is eight in 10.

Now, some nontheists -- an umbrella term that includes atheists, humanists, skeptics and other "freethinkers" -- say the trend may be changing.

"There has been an absolute sea change," said Dale McGowan, executive director of the Georgia-based Foundation Beyond Belief, one of several charities founded in the last five years by and for nonbelievers. "Giving has really become much more of a front-and-center concern for our community."

Recent activity at some charitable organizations support McGowan's statement:

Last year, Reddit atheists raised a total of $50,000 for Doctors Without Borders. This year, they've raised more than $207,000 -- exceeding their goal of $200,000.

In November, Kiva, a micro-financing organization, reported an atheist group raised the highest amount, $271,150. In third place were Kiva Christians with $146,450.

During its first year in operation, the Foundation Beyond Belief raised $83,535 in 2010. This year, that figure should hit $140,500, McGowan said.

What's behind the change? Theories range from the influx of younger nontheists with a focus on global welfare, to images of natural disasters made ubiquitous by the Internet, to the growth in population of people who say they have no religion -- 15 percent, according to the 2008 American Religious Identification Survey.

"When I came into the community (in 1999), it was a monthly meeting and a lecture," McGowan said. "It was a terribly sterile thing ... But the increase of regular folks identifying as nontheists brought with it regular concerns. They want a community, they want to talk about ethics, they want to be doing good works."

Susan Jacoby, who writes an online column on atheism for The Washington Post, said the Brooks numbers -- though questioned by some as inflated -- shocked the nonreligious into action. Many felt they were "good without God."

"But there is no denying that there is a big gap between what religious people give and what secularists give," she said. "And if part of your morality really is about taking care of your fellow man, you are going to start thinking about this."

A turning point came in late 2004, when an earthquake and subsequent tsunami devastated Indonesia and Southeast Asia, killing more than 230,000.

"Boom, the beginning of 2005 was when these organizations started," McGowan said. "Because our members called up and said, 'What can we do for these people?'"

That year saw the founding of Secular Humanist Aid and Relief Effort (SHARE) by the Council for Secular Humanism (now called Skeptics and Humanists Aid and Relief Effort, and operated by the Center for Inquiry), and Humanist Charities by the American Humanist Association.

The Richard Dawkins Foundation, founded by the prominent British atheist and evolutionary biologist, established the Non-Believers Giving Aid Disaster Relief Fund after the Haitian earthquake of January 2010.

"There has been a general awakening to the fact that nontheists of all stripes need to stand up and show the positive values we have," said Roy Speckhardt, executive director of AHA. "We realized the benefit of doing this in a public way, in being clear about we are people who want to care about people."

At the same time, people under 30 -- the so-called "Millennial Generation" -- have brought a different set of concerns to nontheism. The ARIS report shows that more than one in five (22 percent) of Americans between 18 and 29 identify as having no religion.

"Millennials are going to do a lot of good in the world," said Greg Epstein, the Humanist chaplain at Harvard University and the author of "Good Without God."

"They believe you should be vocal about who you are. This is a real change because it means they believe if you are a humanist and believe in its principles you should go out and say so."

Harvard's nontheists have spent spring breaks building houses in New Orleans, worked with homeless youth in Los Angeles and with Native American kids in South Dakota. At Thanksgiving, a feed-the-needy event sponsored by the group was among the biggest events on campus, Epstein said.

Also contributing to the change is the aging of older nontheists, who are beginning to think about legacy.

"I gave almost nothing to charity for most of my adult life," Jacoby said. That changed when her partner of 30 years died and she began to think about living out her values.

"When death is around you, it underscores that, as a secularist, you know this is all there is. You get one chance, and not to be giving when life is finite reminds you of that."